Continuous paracervical anesthesia method and device

ABSTRACT

A medical instrument and method for use in obstetrical or gynecological analgesic procedures to allow the administration of a paracervical block continuously or intermittently with only a single placement. The device has improved retention means, in the form of an inflatable bladder, which minimizes the trauma of insertion and withdrawal while positively assuring retention once the device is inserted in place.

United States atet Inventor Charles A. White 328 Highland Drive, lowa City, Iowa 52240 Appl. No 7,763

Filed Feb. 2, 1970 Patented Aug. 10, 1971 CONTINUOUS PARACERVICAL ANESTHESIA 3,050,066 8/1962 Koehn 128/349 3,173,418 3/1965 Baran 128/351 3,211,151 10/1965 Foderick et al 4 r 128/349 3,308,819 3/1967 128/215 3,358,684 12/1967 l28/214.4 3,508,545 4/1970 128/215 3,539,034 11/1970 128/221 Primary Examiner-Richard A. Gaudet Assistant Examiner-J. B. Mitchell Alt0meysl-1aven E. Simmons and James C. Nemmcrs ABSTRACT: A medical instrument and method for use in obstetrical or gynecological analgesic procedures to allow the administration of a paracervical block continuously or intermittently with only a single placement. The device has improved retention means, in the form of an inflatable bladder, which minimizes the trauma of insertion and withdrawal while positively assuring retention once the device is inserted in place.

PATENTED AUG] 0 am I N VIiN'l M v CHARLES A. WHITE A T TORNE Y BACKGROUND OF THE INVENTION In recent years, the paracervical block has been known and increasingly used as an effective method of regional anesthesia in obstetrics and also in certain gynecological procedures. It is principally used to minimize pain during the first stage of labor. Different techniques and instruments have been recently devised for allowing the anesthetic agent to be administered either continuously or intermittently with only a single placement of the instrument. Techniques which require only a single placement have distinct advantages since the inconvenience of repeated manipulations is eliminated and sin gle placement minimizes the possibility of unnecessary contamination and trauma which might result from using other techniques which require repeated manipulations. However, with any single placement technique, there is always the problem of proper retention of the administration unit. In other words, since the unit must remain in place sometimes for several hours, movement of the patient as well as cervical dilatation during the first stage of labor can cause the unit to become dislodged thus requiring further manipulation to replace the unit. Where replacement becomes necessary, the advantages of the single placement technique of administering the block are, in part, diminished.

There is known to me in the prior art various methods of retaining the paracervical unit in place. These methods use sutures, retention barbs, or precurved distal ends of the catheter. However, with the prior art devices, the more reliable the retention method used, the more traumatic the introduction and removal of the catheter. Of course, one of the reasons for utilizing a device which allows continuous administration of the anesthetic agent is to minimize the trauma to the vaginal mucosa, and if the method of retention increases the trauma,

one of the advantages is lost.

SUMMARY OF THE INVENTION I have devised an improved method and device to allow the administration of a paracervical block continuously or intermittently with only a single placement of the anesthesia unit. My invention also provides an improved method of retention of the unit which greatly minimizes the trauma of insertion and completely eliminates the trauma of withdrawal while assuring positive retention under almost all conditions, including fetal and placenta expulsion and manual exploration during labor. In my improved device, I provide two concentric tubes, the inside tube providing for excursion of the needle for initial insertion and for introducing the anesthetic agent, and the outer tube serving as an introducer and also providing a passageway for the flow of fluid to an inflatable retention bladder at the distal end of the unit. With my novel method and device, retention is positively assured by means of the inflatable bladder, and the trauma of introduction is minimized and the trauma of withdrawal eliminated since the insertion and withdrawal are accomplished while the bladder is in a deflated condition.

The advantages and features of the invention will be readily apparent from a consideration of the description contained herein taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view ofa complete unit constructed according to the principles of my invention and showing the insertion needle in place and the unit in position at the placement site;

FIG. 2 is an enlarged view of the distal end ofthe unit, partly in section, and showing the unit in position at the placement site;

FIG. 3 is an enlarged view of the distal end of the unit similar to FIG. 2 but showing the needle introduced into the tissue at the placement site;

FIG. 4 is an enlarged view of the distal end of the unit similar to FIGS. 2 and 3 but showing the unit in place with the retention bladder inflated and with the insertion needle not withdrawn; and

FIG. 5 is a longitudinal sectional view of a portion of the unit and showing the details of the proximal end of the tubes.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION As previously indicated, the device of the invention is for use in the administration of paracervical anesthesia during the first stage of labor or during certain gynecological procedures such as dilatation and curettage. Paracervical blocks have proved to be effective in relieving pain occurring during the first stage of labor. When used during the first stage of labor, which may extend over several hours, repeated intermittent injections of the anesthetic solution are often necessary. In order to eliminate the necessity for repeated manipulations and the trauma of repeated needle insertions, my invention employs an indwelling anesthesia unit indicated generally by the reference numeral 10. The unit includes an elongated, hollow external tube 12 having an open distal end 14 and a proximal end 15 which flares outwardly. The external tube 12 is preferably made of a smooth, soft and pliable plastic material which can be sterilized. An internal, hollow tube 16 is received inside of the external tube 12 and extends throughout its length and terminates at the opening in the distal end I4. This forms an annular space 18 between tubes 12 and 16. Internal tube 16 communicates with the opening in the distal end l4 and extends beyond the proximal end I5 terminating in an injection adapter cap 20. The internal tube I6 is also of a soft pliable plastic material similar to that used for the external tube 12. At the point where the internal tube 16 enters the proximal end 15 of the external tube 12 a fluidtight seal is provided by the plug 17.

Freely movable inside of the internal tube I6 is a hollow long needle 22 which also has an adapter cap 24 on its proximal end. The needle 22 is preferably of stainless steel or other suitable material. If desired, a stylet (not shown) may be contained inside the needle 22 during insertion of the unit. When the needle 22 is in place in the internal tube 16, the assembled unit as shown in FIG. I is more rigid because of the rigidity of the needle 22, but the unit does retain considerable flexibility. The length of the needle 22 is such that when the needle 22 is moved to the point of maximum penetration with the adapter cap 24 seated against the outer end of the adapter cap 20 the distal end of the needle 22 will protrude a short distance beyond the distal end I4 of the tube I2 (see FIG. 3). Obviously, the needle 22 can be withdrawn completely from the internal tube 16.

Also connected at the proximal end 15 and communicating with the interior of tube 12 is a fluid supply tube 26. This tube 26 terminates at its proximal end in an adapter cap 28 suitable for connection to a source of fluid supply as more fully described hereinafter. If desired, a removable plug 30 can be provided for temporarily closing off the proximal end of the fluid supply tube 26 until its use. The fluid supply tube 26 extends through the plug I7 in the proximal end I5 of the external tube 12 and communicates with the annular space 18 formed between the exterior wall of internal tube 16 and the interior wall of external tube I2. Spaced from its distal end 14 there is provided in the external tube 12 several radially extending openings 32 surrounding which is a relatively thin stretchable bladder 34. Bladder 34 encloses the openings 32 and is sealed to the exterior surface of the tube I2 so that fluid introduced through supply tube 26 and discharged through the openings 32 will create pressure to expand the bladder 34. Of course, tube I2 is sealed at its distal end 14 to the internal tube 16 so that openings 32 provide the only discharge from annular space 18. Thus, if fluid is introduced under sufl'icient pressure through the fluid supply tube 26 into the annular space I8 the bladder 34 will be inflated.

It will be observed in H6. 1 that there is an enlargement 36 formed on the exterior surface of the tube 12 between the distal end 14 and proximal end 157 This enlargement 36 serves the purpose of allowing the physician to determine the depth of penetration of the instrument into the tissue, as will be described more fully hereinafter.

The function of the various components of the unit and the procedure for their use will now be described. When the physician has determined that the paracervical block should be used, the unit is inserted into the vagina 38 of the patient and manually guided by the physician until the distal end 14 is positioned immediately lateral to the cervix 40 and against the broad ligament 42. Insertion is facilitated by the rigidity of the unit owing to the position of the needle 22 within the internal tube 16. It should be noted, however, that during insertion the distal end of the needle 22 does not protrude, it being withdrawn into the internal tube 16. With the unit 10 properly positioned, the needle 22 is advanced until it penetrates the mucosa of the vagina 38. The extent to which the needle 22 can be advanced is limited by contact of the needles adapter cap 24 with the adapter cap on the proximal end of the tube 16. When the initial puncture has been made, the entire unit 10 is then advanced until the bladder 34 has penetrated the vaginal mucosa. This is illustrated in FIG. 4. The enlargement 36 on the exterior of the tube 12 is used by the physician as a gauge to insure the penetration has been sufficiently deep but not excessive. When the bladder 34 has penetrated the vaginal mucosa, fluid is then introduced through the fluid supply tube 26 to inflatc the bladder 34. Fluid pressure is thereafter maintained as long as it is necessary to keep the bladder 34 inflated. With the bladder 34 inflated, the unit cannot be withdrawn. Moreover, the possibility is greatly minimized of the unit becoming dislodged during further dilation of the cervix, during obstetrical manipulations or dislodged by advancement of the fetus or expulsion of the placenta. With the unit thus being retained in place by bladder 34, the anesthetic solution can be introduced into the tissue through the hollow needle 22 continuously or at required intervals to produce the desired analgesic effect. The needle 22 is sufficiently flexible that it can be retained in the unit throughout the entire procedure, although usually it is preferable to withdraw the needle and insert in the adapter cap 24 a hypodermic needle at the time injection of the anesthetic is to be made. Without the needle 22, the unit 10 is sufficiently long and flexible that after placement it can be taped or otherwise affixed to the thighs or abdomen of the patient. Normally, two of the units will be used during each procedure, so that the anesthetic solution can be introduced into the broad ligaments 42 on opposite sides of the cervix 40.

When the unit 10 is to be removed, the fluid pressure that has been continuously applied through the supply tube 26 to the bladder 34 is relieved and the bladder 34 will be deflated allowing easy nontraumatic withdrawal of the unit. Because of my novel design of the anesthetic unit and the method of retaining it in place, it is obvious that the trauma of insertion is kept to a minimum. Moreover, the trauma of withdrawal, unlike some of the prior art units, is completely eliminated. The unit provides a method of retention which makes it virtually impossible to inadvertently dislodge the unitv The unit is very simple, is inexpensive, and has all the advantages of prior art continuous paracervical devices but has improved retention and causes less trauma. Preferably, all the tubes which form the principal parts of the unit are made of transparent or translucent material so that visual checks of fluid or aspirated blood in the tubes can be conducted. Moreover, it will be obvious to those skilled in the art that various revisions and modifications can be made in the preferred embodiment of the unit described herein without departing from the spirit and scope of the invention. It is my intention, however, that all such revisions and modifications as are obvious to those skilled in the art will be included within the scope of the following claims.

] claim: 1. A device for administering a fluid agent into body tissue through an opening in the body, said device comprising a longitudinally extending hollow tube having a distal end and a proximal end, said distal end being open, means at the distal end for puncturing the said tissue, said means for puncturing the tissue including an elongated needle longitudinally movable within said tube, said needle being extendible through the opening in said distal end, an expandable member surrounding said tube near said distal end, means for selectively expanding and contracting said expandable member, and means for introducing the fluid agent into said tube for discharge through the opening in said distal end.

2. The device of claim I in which the means for introducing the fluid agent into the tube includes said needle.

3. The device of claim I in which said means for selectively expanding and contracting said expandable member includes an inner hollow tube contained within said first mentioned hollow tube and forming an annular space therebetween, said first hollow tube having at least one opening therein to provide for communication between said annular space and said expandable member.

4. The device of claim 3 in which said means for puncturing the said tissue includes an elongated needle longitudinally movable within said inner tube, said needle being extendible through the opening in said distal end.

5. The device ofclaini 4 in which said means for introducing the fluid agent includes said needle.

6. The device of claim 4 in which the annular space formed between said first hollow tube and said inner tube is sealed at the distal and proximal ends, and means is provided to connect said annular space to a source of fluid supply.

7. The device of claim 4 in which said inner tube extends beyond the proximal end of said first hollow tube, and said needle is of a length slightly longer than the length of said inner tube so that said needle will protrude slightly from said distal end when fully advanced in said inner tube.

8. A method for administering a fluid agent into body tissue through an opening in the body, said method comprising the steps of inserting a hollow tubular member through said body opening until the end thereof is placed against the tissue into which the agent is to be injected; puncturing the tissue at the placement site; inserting the device a limited distance into the tissue through said puncture; expanding the size of said device at a point within the tissue; injecting the agent through said device into said tissue; contracting the expanded portion of said device; and withdrawing said device from said tissue and through said body opening.

9. The method of claim 8 in which said device is left in place over a period of time and said agent is continuously injected through said device into said tissue.

10. The method of claim 8 in which said device is left in place over a period of time, and said agent is intermittantly and repeatedly injected through said device into said tissue, 

1. A device for administering a fluid agent into body tissue through an opening in the body, said device comprising a longitudinally extending hollow tube having a distal end and a proximal end, said distal end being open, means at the distal end for puncturing the said tissue, said means for puncturing the tissue including an elongated needle longitudinally movable within said tube, said needle being extendible through the opening in said distal end, an expandable member surrounding said tube near said distal end, means for selectively expanding and contracting said expandable member, and means for introducing the fluid agent into said tube for discharge through the opening in said distal end.
 2. The device of claim 1 in which the means for introducing the fluid agent into the tube includes said needle.
 3. The device of claim 1 in which said means for selectively expanding and contracting said expandable member includes an inner hollow tube contained within said first mentioned hollow tube and forming an annular space therebetween, said first hollow tube having at least one opening therein to provide for communication between said annular space and said expandable member.
 4. The device of claim 3 in which said means for puncturing the said tissue includes an elongated needle longitudinally movable within said inner tube, said needle being extendible through the opening in said distal end.
 5. The device of claim 4 in which said means for introducing the fluid agent includes said needle.
 6. The device of claim 4 in which the annular space formed between said first hollow tube and said inner tube is sealed at the distal and proximal ends, and means is provided to connect said annular space to a source of fluid supply.
 7. The device of claim 4 in which said inner tube extends beyond the proximal end of said first hollow tube, and said needle is of a length slightly longer than the length of said inner tube so that said needle will protrude slightly from said distal end when fully advanced in said inner tube.
 8. A method for administering a fluid agent into body tissue through an opening in the body, said method comprising the steps of inserting a hollow tubular member through said body opening until the end thereof is placed against the tissue into which the agent is to be injected; puncturing the tissue at the placement site; inserting the device a limited distance into the tissue through said puncture; expanding the size of said device at a point within the tissue; injecting the agent through said device into said tissue; contracting the expanded portion of said Device; and withdrawing said device from said tissue and through said body opening.
 9. The method of claim 8 in which said device is left in place over a period of time and said agent is continuously injected through said device into said tissue.
 10. The method of claim 8 in which said device is left in place over a period of time, and said agent is intermittantly and repeatedly injected through said device into said tissue. 